ORAU Team

NIOSH Dose Reconstruction Project 

Technical Basis Document for Portsmouth Gaseous 

Diffusion Plant - Introduction

Document Number:

ORAUT-TKBS-0015-1 

Effective Date: 05/11/2004

Revision No.: 00

Controlled Copy No.:

Page 1 of 7

Subject Expert: Mark D. Notich

Document Owner

Approval: Signature on File Date:

Mark Notich, TBD Team Leader

05/06/2004

Approval: Signature on File Date:

Judson L. Kenoyer, Task 3 Manager

05/11/2004

Concurrence: Signature on File Date:

Richard E. Toohey, Project Director

05/11/2004

Approval: Signature on File Date:

James W. Neton, OCAS Health Science Administrator

05/11/2004

Supersedes:

 None

TABLE OF CONTENTS

Section Page

RECORD OF REVISION ..................................................................................................................... 2 

ACRONYMS AND ABBREVIATIONS.................................................................................................. 3 

1.0 PURPOSE............................................................................................................................... 4 

2.0 SCOPE.................................................................................................................................... 5 

REFERENCES.................................................................................................................................... 6 
Effective Date: 05/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0015-1 Page 2 of 6

RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION

DATE

EFFECTIVE 

DATE

REV.

NO. DESCRIPTION

Draft 04/09/2004 00-A New technical basis document for the Portsmouth 

Gaseous Diffusion Plant – Site Profile. Initiated by 

Mark D. Notich

Draft 04/20/2004 00-B Incorporates NIOSH comments. Initiated by Mark 

D. Notich.

Draft 05/05/2004 00-C Incorporates additional NIOSH comments. 

Initiated by Mark D. Notich.

05/11/2004 05/11/2004 00 First approved issue of revision 00. Initiated by 

Mark D. Notich.
Effective Date: 05/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0015-1 Page 3 of 6

ACRONYMS AND ABBREVIATIONS

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

DOE Department of Energy

DOL Department of Labor

GM Geiger-Muller 

HHS Department of Health and Human Services

ICPMS Inductively Coupled Plasma Mass Spectrometry

NIOSH National Institute for Occupational Safety and Health

ORAU Oak Ridge Associated Universities

OWCP Office of Worker Compensation

PORTS Portsmouth Gaseous Diffusion Plant

TBD technical basis document

TLD thermoluminescent detectors
Effective Date: 05/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0015-1 Page 4 of 6

1.0 PURPOSE

This Site Profile represents a specific support mechanism concerning documentation of historical 

practices at the Portsmouth Gaseous Diffusion Plant (PORTS). This Site Profile can be used to 

evaluate both internal and external dosimetry data for monitored workers and can serve as a 

supplement to individual monitoring data. For unmonitored workers, information is present in this 

document that will provide for estimations of internal and external doses. This document provides a 

site profile of PORTS that contains technical basis information to be used to evaluate the total 

occupational radiation dose for EEOICPA claimants. 

This document also provides supporting technical data to evaluate the total PORTS occupational 

radiation dose that may reasonably be associated with the worker’s radiation exposure. This dose 

results from exposure to external and internal radiation sources in PORTS facilities, to PORTS 

occupationally-required diagnostic x-ray examinations, and to on-site environmental releases. Also 

included are techniques to estimate the dose that may have occurred while an employee was not 

monitored, inadequately monitored, dose that may have been missed due to analytical detection 

limits, or whose monitoring records are incomplete or missing (i.e., missed dose). Over the years new 

and more reliable scientific methods and protection measures have been deployed. The methods 

needed to account for these changes are also identified in this document.

The doses are evaluated using the NIOSH Interactive RadioEpidemiological Program and the 

Integrated Modules for Bioassay Analysis (IMBA) computer program. Information on measurement 

uncertainties is an integral component of the NIOSH approach. This document describes how to 

evaluate uncertainty associated with PORTS exposure and dosimetry records.

Technical Basis Documents (TBD) and Site Profile Documents are general working documents that 

provide guidance concerning the preparation of dose reconstructions at particular sites or categories 

of sites. They will be revised in the event additional relevant information is obtained about the 

affected site(s). These documents may be used to assist NIOSH in the completion of the individual 

work required for each dose reconstruction.

In this document the word “facility” is used as a general term for an area, building or group of buildings 

that served a specific purpose at a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy facility” as defined in the Energy Employee 

Occupational Illness Compensation Program Act of 2000 (42 U.S.C. § 73841 (5) and (12)).

2.0 SCOPE

The document is divided into six major sections: this Introduction, Site Description, Occupational 

Medical Dose, Occupational Environmental Dose, Occupational Internal Dose, and Occupational 

External Dosimetry. Some sections are accompanied by an attachment that provides the critical data 

for the specialists reconstructing the doses.

The Site Description TBD (ORAUT-TKBS-0015-2) presents a brief description of the facilities and 

processes that have been used in processing and enriching uranium. PORTS processed thousands 

of tons of uranium through diffusion cascades for 47 years beginning in 1954. The majority of the 

uranium feed materials PORTS received was slightly enriched from Paducah, but some was recycled 

material obtained from spent reactor fuel.
Effective Date: 05/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0015-1 Page 5 of 6

The Occupational Medical Dose TBD (ORAUT-TKBS-0015-3) provides information about the dose 

that individual workers received from x-rays that were required as a condition of employment. These 

x-rays included pre-employment and annual chest x-rays. All employees were required to have 

annual chest x-rays from 1954 to 1989. In 1990, chest x-rays were offered on a frequency based on 

the age of the employee but asbestos/beryllium workers were still required to have annual chest xrays.

Both the x-ray equipment and the techniques used for taking x-rays have changed over the years 

covered by this Site Profile. These factors were taken into account in estimating the dose that a 

worker would have received from the x-ray. The parameters considered included the tube current and 

voltage, exposure time, filtration, source to skin distance, the view (posterior-anterior or lateral), and 

any other factor that could affect the dose received by the worker.

The doses to other exposed organs from the chest x-ray have also been calculated. The calculated 

dose also takes into account the uncertainty associated with each of the parameters mentioned 

above. The doses received by the various organs in the body are presented in the tables for 

convenient reference for dose reconstruction.

The Occupational Environmental Dose TBD (ORAUT-TKBS-0015-4) applies to workers who were not 

monitored for external or internal radiation exposure. The environmental dose is the dose workers 

received when working outside the buildings on the site from inhalation of radioactive materials in the 

air, direct radiation from plumes, contact with particles on the skin, and from direct exposure to 

radionuclides incorporated in the soil.

Inhalation of environmental radionuclides results in internal dose to the whole body or body organs. 

Whole- or partial-body external dose results from deposited radionuclides or submersion in a cloud of 

radioactive material.

The internal dose for workers outside of the facilities was determined from the air concentrations 

resulting from the releases from stacks, individual building releases, and from the purge cascade and 

other operations at PORTS. Unmonitored workers may have been exposed to occupational doses 

internally from on-site releases into the air.

The air concentration of radionuclides was determined using the annual environmental reports from 

1972 and 2001 and a special study of historic radiological releases (Goslow 1986) to estimate 

radionuclide-specific airborne concentrations for 234, 235, 236, 238U, Pu, Np, 99Tc, and uranium daughters 

(

231, 234Th, 234mPa). The uranium isotopes were monitored from the onset of plant operations with the 

Np, Pu, Tc, and uranium daughters being added to the monitoring program at later dates beginning in 

1967. 

The external dose to workers from the ambient radiation levels on-site and from submersion in a cloud 

of radioactive material were estimated from on-site environmental monitoring equipment such as 

Geiger-Muller (GM) tubes and thermoluminescent detectors (TLDs). 

Several accidental releases of uranium occurred during the operational period of PORTS. The largest 

of these releases occurred in 1978 when a 14-ton feed cylinder fell and cracked open, releasing an 

estimated 4,820 kg of uranium to the atmosphere and an additional 680 kg of uranium to the plant 

sewers. In addition, a string of accidental releases of mostly depleted uranium during the first five 

years of plant operation accounted for essentially all of the uranium lost to the atmosphere from 1955 

through 1958 and 20% of the losses in 1959.
Effective Date: 05/11/2004 Revision No. 00 Document No. ORAUT-TKBS-0015-1 Page 6 of 6

The Occupational Internal Dosimetry TBD (ORAUT-TKBS-0015-5) describes the internal dosimetry 

program at PORTS. The PORTS internal dosimetry program for uranium isotopes started when the 

site began operations in 1954. Routine monitoring for 99Tc began in 1965 in vivo and 1975 in vitro. 

Transuranics have not been monitored routinely with the exception of 237 Np. 

Urine analysis for total alpha activity began at the start of operations in 1954. Fluorimetry and gas flow 

proportional counting was employed until 1995 when Inductively Coupled Plasma Mass Spectrometry 

(ICPMS) was utilized. The frequency of urine analysis at PORTS varied considerably and was based 

on the potential for the individual to come into contact with radioactive materials. Additional urine 

analyses were performed based on recalls (lost or inadequate samples, or abnormal results) or 

supervisor’s request. Urine analysis for 99Tc began in 1965 using a liquid scintillation method and 

subsequent subtraction of the uranium/thorium complement to yield the 99Tc results. Routine 

monitoring for transuranics has not been conducted at PORTS. In vivo analyses began in 1965 to 

detect non-transportable or insoluble compounds such as U3O8 and 99Tc in the lungs.

Interferences that may be encountered in the collection and analysis of urine samples are discussed, 

as are the uncertainties in the urine analysis measurements. Also presented is information that may 

be useful in estimating possible missed doses due the limitation of the monitoring practices as well as 

the limitations of the equipment and techniques for radiation detection and measurement. Methods 

for evaluating potential doses that may fall into this category are presented.

The Occupational External Dosimetry Program TBD (ORAUT-TKBS-0015-6) discusses the program 

for measuring skin and whole body doses to the workers. The methods for evaluating external doses 

to workers have also evolved over the years as new techniques and equipment have been developed. 

In addition, concepts in radiation protection have changed. The dose reconstruction, PORTS 

practices and policies, and dosimeter types and technology for measuring the dose from the different 

types of radiation are discussed in this section. Attention is given to the evaluation of doses measured 

from exposure to beta, gamma, and neutron radiation.

Sources of bias, workplace radiation field characteristics, responses to different beta/gamma and 

neutron dosimeters in the workplace fields, and the adjustments to the recorded dose measured by 

these dosimeters during specific years are discussed in detail.

There are sources of potential dose that could be missed because of the limitations of dosimetry 

systems and the methods of reporting low doses. This potentially missed dose is discussed as a 

function of dosimeter type, year, and type of radiation.

REFERENCES

Goslow, G. A., 1986. Historical Radionuclide Release Report, GAT-1124, Goodyear Atomic 

Corporation, Piketon, Ohio, January.